Segment Reporting (Parenthetical) (Detail) - USD ($) $ in Thousands		3 Months Ended								12 Months Ended
		Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Segment Reporting Information [Line Items]
Net revenues		$ 2,754,496	$ 2,648,913	$ 2,681,353	$ 2,687,516	$ 2,642,787	$ 2,541,864	$ 2,612,356	$ 2,612,858	$ 10,772,278	$ 10,409,865	$ 9,766,210
Total assets		11,265,480				10,761,828				11,265,480	10,761,828	10,317,802
Provision For asset impairment										49,310	0	0
Behavioral Health Services
Segment Reporting Information [Line Items]
Net revenues	[1]									5,038,874	4,906,719	4,645,007
Total assets	[1]	6,786,369				6,648,818				6,786,369	6,648,818	6,440,195
Behavioral Health Services | Located in U.K.
Segment Reporting Information [Line Items]
Net revenues										505,000	429,000	241,000
Total assets		$ 1,224				$ 1,098				1,224	$ 1,098	$ 965,000
Foundations Tradename | Behavioral Health Services
Segment Reporting Information [Line Items]
Provision For asset impairment										$ 49,000

[1] Includes net revenues generated from our behavioral health care facilities located in the U.K. amounting to approximately $505 million in 2018, $429 million in 2017 and $241 million in 2016. Total assets at our U.K. behavioral health care facilities were approximately $1.224 billion as of December 31, 2018, $1.098 billion as of December 31, 2017 and $965 million as of December 31, 2016. In addition, included in our 2018 Behavioral Health Services operating segment Income (loss) before allocation of corporate overhead and income taxes is a pre-tax $49 million provision for asset impairment to reduce the carrying value of a tradename intangible asset.